Mechanism of tribo-induced structure modification for nanocomposite Mo–S–C–H thin film coatings

Comparative studies of the tribological properties of solid lubricant coatings of three main types (MoS$_2$, $a$-C(H)) and Mo–S–C–H in an inert gas medium have been carried out. It has been established that the coefficient of friction for the Mo–S–C–H nanocomposite coating is somewhat higher than for the other two. And its wear resistance is comparable to $a$-C(H) and higher than that of MoS$_2$. The friction coefficient of the Mo–S–C–H coating was determined by the nature of tribo-induced surface modification. It included the formation of a nanofilm with a thickness of 6 nm and layered atomic packing characteristic of the MoS$_2$ phase and graphitization of the $a$-C(H) nanophase, which was accumulated in wear debris.